Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752978AbdGHQFk (ORCPT ); Sat, 8 Jul 2017 12:05:40 -0400 Received: from mail-qk0-f195.google.com ([209.85.220.195]:34045 "EHLO mail-qk0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752810AbdGHQFi (ORCPT ); Sat, 8 Jul 2017 12:05:38 -0400 MIME-Version: 1.0 In-Reply-To: <20170708000303.21863-2-dbasehore@chromium.org> References: <20170708000303.21863-1-dbasehore@chromium.org> <20170708000303.21863-2-dbasehore@chromium.org> From: Andy Shevchenko Date: Sat, 8 Jul 2017 19:05:37 +0300 Message-ID: Subject: Re: [PATCH v5 2/5] tick: Add freeze timer events To: Derek Basehore Cc: "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , Rajneesh Bhardwaj , "x86@kernel.org" , Platform Driver , "Rafael J . Wysocki" , Len Brown , "linux-pm@vger.kernel.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1644 Lines: 55 On Sat, Jul 8, 2017 at 3:03 AM, Derek Basehore wrote: > Adds a new feature to tick to schedule wakeups on a CPU during freeze. > This won't fully wake up the system (devices are not resumed), but > allow simple platform functionality to be run during freeze with > little power impact. > > This implementation allows an idle driver to setup a timer event with > the clock event device when entering freeze by calling > tick_set_freeze_event. Only one caller should exist for the function. > > tick_freeze_event_expired is used to check if the timer went off when > the CPU wakes. > > The event is cleared by tick_clear_freeze_event. > +int tick_set_freeze_event(int cpu, ktime_t delta) > +{ > + printk_deferred(KERN_WARNING > + "[%s] unsupported by clock event device\n", Can it be one line? > + printk_deferred(KERN_WARNING > + "[%s] clock event device in use\n", Ditto. > + printk_deferred(KERN_WARNING > + "[%s] %lluns outside range: [%lluns, %lluns]\n", Ditto. > + printk_deferred(KERN_WARNING > + "Failed to program freeze event\n"); Ditto. > +int tick_freeze_event_expired(int cpu) > +{ > + struct clock_event_device *dev = per_cpu(tick_cpu_device, cpu).evtdev; > + > + if (!(dev && dev->event_expired)) Usually we use a pattern (!x || !x->y). At least for me it looks slightly better to read. > + return 0; > + > + return dev->event_expired(dev); > +} -- With Best Regards, Andy Shevchenko